The goal of this project is to examine the effect of naltrexone, an opioid antagonist, on voluntary alcohol consumption in nontreatment seeking alcohol dependent volunteers using a laboratory self-administration paradigm. The specifics are:1) to determine whether subjects on naltrexone exhibit greater reductions in voluntary alcohol consumption than subjects on placebo; 2) to determine whether naltrexone modifies the subjective and neuorendocrine responses to alcohol; 3) to evaluate whether the subjective and neuroendocrine responses to alcohol predict further voluntary alcohol consumption; 4) to determine whether naltrexone differentially affects voluntary alcohol consumption and responses to alcohol in men and women; and 5) to determine if naltrexone alters anxiety in response to a stressor.